246 research outputs found
Surviving the business life cycle : a theoretical framework for independent financial advisers
Independent financial advisers play a vital role in assisting clients to meet their financial goals. However, it appears that additional guidance is needed for these advisers to survive in their complex business environment, governed by strict legislation. To date, only a small amount of research has been conducted in this area and no formal research study in South Africa has provided a course of direction for these advisers. Consequently, this study aimed to expand the body of knowledge by investigating the potential problems posing a threat to the businesses of independent financial advisers in their business life cycle, as well as possible strategies that can be implemented to counter those obstacles. Based on the findings a theoretical framework was proposed, suggesting key areas independent financial advisers would need to focus on in their business life cycle to conquer the challenges they might encounter and survive. The study concluded with a number of hypotheses to set the direction for future empirical research regarding the survival and growth of independent financial advisers in South Africa
Evaluation of an initiative providing omega-3 rich snacks to preschool children in a deprived area of Edinburgh
sch_dieunpub1808unpu
Detailed study of the GRB 030329 radio afterglow deep into the non-relativistic phase
We explore the physics behind one of the brightest radio afterglows ever, GRB
030329, at late times when the jet is non-relativistic. We determine the
physical parameters of the blast wave and its surroundings, in particular the
index of the electron energy distribution, the energy of the blast wave, and
the density (structure) of the circumburst medium. We then compare our results
with those from image size measurements. We observed the GRB 030329 radio
afterglow with the Westerbork Synthesis Radio Telescope and the Giant Metrewave
Radio Telescope at frequencies from 325 MHz to 8.4 GHz, spanning a time range
of 268-1128 days after the burst. We modeled all the available radio data and
derived the physical parameters. The index of the electron energy distribution
is p=2.1, the circumburst medium is homogeneous, and the transition to the
non-relativistic phase happens at t_NR ~ 80 days. The energy of the blast wave
and density of the surrounding medium are comparable to previous findings. Our
findings indicate that the blast wave is roughly spherical at t_NR, and they
agree with the implications from the VLBI studies of image size evolution. It
is not clear from the presented dataset whether we have seen emission from the
counter jet or not. We predict that the Low Frequency Array will be able to
observe the afterglow of GRB 030329 and many other radio afterglows,
constraining the physics of the blast wave during its non-relativistic phase
even further.Comment: 9 pages, 2 figures; accepted for publication in Astronomy &
Astrophysics after minor revisions; small changes in GMRT fluxes at 1280 MH
The LOFAR Transients Pipeline
Current and future astronomical survey facilities provide a remarkably rich
opportunity for transient astronomy, combining unprecedented fields of view
with high sensitivity and the ability to access previously unexplored
wavelength regimes. This is particularly true of LOFAR, a
recently-commissioned, low-frequency radio interferometer, based in the
Netherlands and with stations across Europe. The identification of and response
to transients is one of LOFAR's key science goals. However, the large data
volumes which LOFAR produces, combined with the scientific requirement for
rapid response, make automation essential. To support this, we have developed
the LOFAR Transients Pipeline, or TraP. The TraP ingests multi-frequency image
data from LOFAR or other instruments and searches it for transients and
variables, providing automatic alerts of significant detections and populating
a lightcurve database for further analysis by astronomers. Here, we discuss the
scientific goals of the TraP and how it has been designed to meet them. We
describe its implementation, including both the algorithms adopted to maximize
performance as well as the development methodology used to ensure it is robust
and reliable, particularly in the presence of artefacts typical of radio
astronomy imaging. Finally, we report on a series of tests of the pipeline
carried out using simulated LOFAR observations with a known population of
transients.Comment: 30 pages, 11 figures; Accepted for publication in Astronomy &
Computing; Code at https://github.com/transientskp/tk
Expansion Dynamics After Laser-Induced Cavitation in Liquid Tin Microdroplets
The cavitation-driven expansion dynamics of liquid tin microdroplets is
investigated, set in motion by the ablative impact of a 15-ps laser pulse. We
combine high-resolution stroboscopic shadowgraphy with an intuitive fluid
dynamic model that includes the onset of fragmentation, and find good agreement
between model and experimental data for two different droplet sizes over a wide
range of laser pulse energies. The dependence of the initial expansion velocity
on these experimental parameters is heuristically captured in a single power
law. Further, the obtained late-time mass distributions are shown to be
governed by a single parameter. These studies are performed under conditions
relevant for plasma light sources for extreme-ultraviolet nanolithography.Comment: 7 pages, 6 figure
An automated archival VLA transients survey
In this paper we present the results of a survey for radio transients using
data obtained from the Very Large Array archive. We have reduced, using a
pipeline procedure, 5037 observations of the most common pointings - i.e. the
calibrator fields. These fields typically contain a relatively bright point
source and are used to calibrate `target' observations: they are therefore
rarely imaged themselves. The observations used span a time range ~ 1984 - 2008
and consist of eight different pointings, three different frequencies (8.4, 4.8
and 1.4 GHz) and have a total observing time of 435 hours. We have searched for
transient and variable radio sources within these observations using components
from the prototype LOFAR transient detection system. In this paper we present
the methodology for reducing large volumes of Very Large Array data; and we
also present a brief overview of the prototype LOFAR transient detection
algorithms. No radio transients were detected in this survey, therefore we
place an upper limit on the snapshot rate of GHz frequency transients > 8.0 mJy
to rho less than or equal to 0.032 deg^-2 that have typical timescales 4.3 to
45.3 days. We compare and contrast our upper limit with the snapshot rates -
derived from either detections or non-detections of transient and variable
radio sources - reported in the literature. When compared with the current Log
N - Log S distribution formed from previous surveys, we show that our upper
limit is consistent with the observed population. Current and future radio
transient surveys will hopefully further constrain these statistics, and
potentially discover dominant transient source populations. In this paper we
also briefly explore the current transient commissioning observations with
LOFAR, and the impact they will make on the field.Comment: Accepted for publication in MNRA
Radiation transport and scaling of optical depth in Nd:YAG laser-produced microdroplet-tin plasma
Experimental scaling relations of the optical depth are presented for the emission spectra of a tin-droplet-based, 1-μm-laser-produced plasma source of extreme-ultraviolet (EUV) light. The observed changes in the complex spectral emission of the plasma over a wide range of droplet diameters (16-65 μm) and laser pulse durations (5-25 ns) are accurately captured in a scaling relation featuring the optical depth of the plasma as a single, pertinent parameter. The scans were performed at a constant laser intensity of 1.4 × 1011 W/cm2, which maximizes the emission in a 2% bandwidth around 13.5 nm relative to the total spectral energy, the bandwidth relevant for industrial EUV lithography. Using a one-dimensional radiation transport model, the relative optical depth of the plasma is found to linearly increase with the droplet size with a slope that increases with the laser pulse duration. For small droplets and short laser pulses, the fraction of light emitted in the 2% bandwidth around 13.5 nm relative to the total spectral energy is shown to reach high values of more than 14%, which may enable conversion efficiencies of Nd:YAG laser light into - industrially - useful EUV radiation rivaling those of current state-of-the-art CO2-laser-driven sources
Light-intensity physical activity is associated with adiposity in adolescent females
peer-reviewedIntroduction: Sedentary behavior (SB) research has relied on accelerometer thresholds to distinguish between sitting/lying time (SLT) and light-intensity physical activity (LIPA). Such methods may misclassify SLT, standing time (StT), and LIPA. This study examines the association between directly measured SB, physical activity (PA), and adiposity in an adolescent female sample. Methods: Female adolescents (n = 195; mean age, 15.7 yr (SD, 0.9)) had body mass index (BMI) (median, 21.7 kg.m(-2) (interquartile range, 5.2 kg.m(-2))) and four-site sum of skinfolds (median, 62.0 mm; interquartile range, 37.1 mm) measured and wore an activPAL (TM) activity monitor for 7 d. SLT, StT, breaks in SLT, and bouts of SLT = 30 min were determined from activPAL outputs. A threshold of 2997 counts per 15 s determined moderate-to-vigorous PA. All remaining time was quantified as LIPA. Mixed linear regression models examined associations between PA variables, SB variables, and adiposity. Results: Participants spent a mean of 65.3% (SD, 7.1) of the waking day in SLT, 23.0% (SD, 5.3) in StT, 5.6% (SD, 1.5) in LIPA, and 6.1% (SD, 2.4) in moderate-to-vigorous PA. Significant effects for the percentage of LIPA (which excluded StT) with both BMI (beta = -4.38, P = 0.0006) and sum of skinfolds (beta = -4.05, P = 0.006) were identified. Significant effects for breaks in SLT with BMI (beta = -0.30, P = 0.04) were also observed. No additional significant associations were found between activity measures and adiposity. Conclusions: Increased LIPA (excluding StT) and breaks in SLT were negatively associated with adiposity in this sample, independent of age. Interventional work should examine whether reducing SLT through breaks and increasing LIPA may prevent increases in adiposity in adolescent females.ACCEPTEDpeer-reviewe
Biofortified red mottled beans (Phaseolus vulgaris L.) in a maize and bean diet provide more bioavailable iron than standard red mottled beans: Studies in poultry (Gallus gallus) and an in vitro digestion/Caco-2 model
<p>Abstract</p> <p>Background</p> <p>Our objective was to compare the capacities of biofortified and standard colored beans to deliver iron (Fe) for hemoglobin synthesis. Two isolines of large-seeded, red mottled Andean beans (<it>Phaseolus vulgaris </it>L.), one standard ("Low Fe") and the other biofortified ("High Fe") in Fe (49 and 71 μg Fe/g, respectively) were used. This commercial class of red mottled beans is the preferred varietal type for most of the Caribbean and Eastern and Southern Africa where almost three quarters of a million hectares are grown. Therefore it is important to know the affect of biofortification of these beans on diets that simulate human feeding studies.</p> <p>Methods</p> <p>Maize-based diets containing the beans were formulated to meet the nutrient requirements for broiler except for Fe (Fe concentrations in the 2 diets were 42.9 ± 1.2 and 54.6 ± 0.9 mg/kg). One day old chicks (<it>Gallus gallus</it>) were allocated to the experimental diets (n = 12). For 4 wk, hemoglobin, feed-consumption and body-weights were measured.</p> <p>Results</p> <p>Hemoglobin maintenance efficiencies (HME) (means ± SEM) were different between groups on days 14 and 21 of the experiment (P < 0.05). Final total body hemoglobin Fe contents were different between the standard (12.58 ± 1.0 mg {0.228 ± 0.01 μmol}) and high Fe (15.04 ± 0.65 mg {0.273 ± 0.01 μmol}) bean groups (P < 0.05). At the end of the experiment, tissue samples were collected from the intestinal duodenum and liver for further analyses. Divalent-metal-transporter-1, duodenal-cytochrome-B, and ferroportin expressions were higher and liver ferritin was lower (P < 0.05) in the standard group vs. the biofortified group. <it>In-vitro </it>analysis showed lower iron bioavailability in cells exposed to standard ("Low Fe") bean based diet.</p> <p>Conclusions</p> <p>We conclude that the <it>in-vivo </it>results support the <it>in-vitro </it>observations; biofortified colored beans contain more bioavailable-iron than standard colored beans. In addition, biofortified beans seems to be a promising vehicle for increasing intakes of bioavailable Fe in human populations that consume these beans as a dietary staple. This justifies further work on the large-seeded Andean beans which are the staple of a large-region of Africa where iron-deficiency anemia is a primary cause of infant death and poor health status.</p
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